The invention relates to the use of the reaction products of polyamines and alkyl glycidyl ethers as foam control agents.
Foam control or elimination in many waterborne applications and industrial processes is critical for obtaining optimal performance in application and high process efficiency. The importance of foam control and elimination in applications such as waterborne coatings, inks, adhesives, and agricultural formulations and in industrial processes such as oil well pumping, petroleum gas scrubbing, cleansing and disinfecting, food processing, pulp and paper processing, fermentation, metal treatment, polymer and chemical synthesis, waste-water treatment and textile dying and finishing is well-appreciated in the art.
Foam control agents are widely used in polymer production and processing, as foam can lead to reduced production capacity, efficiency and equipment problems. In particular, severe foaming problems commonly result upon stripping unreacted monomers from the polymer product.
Undesirable foam can lead to inefficient mixing, poor productivity, reduced vessel capacity and equipment failure in many common industrial processes. For instance, foaming in refinery processes such as drilling, production, stimulation, distillation, extraction, gas and liquid scrubbing and other operations leads to a number of operating difficulties and significant economic consequences. In acid gas sweetening, gases such as carbon dioxide and hydrogen sulfide are removed via scrubbing with an aqueous amine solution. Problematic foam can occur during both the scrubbing or regeneration steps in this process.
Defoamers and antifoams are additives that are used to reduce or eliminate problematic foam. An xe2x80x9cantifoamxe2x80x9d refers to a long-acting agent which prevents foam formation. A xe2x80x9cdefoamerxe2x80x9d is a material that yields rapid knock-down of existing foam. Herein, the term xe2x80x9cfoam control agentxe2x80x9d is used to refer to additives that eliminate and/or control foam since many applications and processes require both foam prevention and reduction or elimination.
In many applications it is desired that foam control agents exhibit positive ancillary surface properties, such as wetting, dispersion, emulsification, solubilization, flow and leveling. For example, defoamers and antifoams that act as wetting agents will greatly reduce surface defects in coatings, inks, adhesives and agricultural formulations. In addition, such multi-functional materials will allow for the reduction or elimination of wetting agents in a waterborne composition, thereby reducing the total amount of additives. The ability of a material to act as a wetting agent in waterborne formulations is assessed by its ability to reduce the surface tension of water. Equilibrium surface tension performance is important when a system is at rest. However, the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are utilized. Such applications include the spraying, rolling and brushing of coatings, adhesives or agricultural formulations, or high-speed gravure or ink-jet printing. Dynamic surface tension is a fundamental quantity which provides a measure of the ability of a substance to reduce surface tension and provide wetting under high-speed application conditions. Also, it is under such high speed application conditions where the entrainment of air and the creation of foam is a problem.
Adducts prepared by the reaction of polyamines with alkyl glycidyl ethers (epoxies) may be found in the literature. Such amines have been utilized in a variety of applications. Depending upon the polyamine, five or more epoxy reagents may be used to form a completely adducted amine. The majority of examples in the literature contain amines which are not fully adducted.
U.S. Pat. No. 4,650,000 discloses adducts prepared by the reaction of polyamines with C6-C18 alkyl glycidyl ethers have been shown to be effective surfactants for the formation of microemulsions containing a hydrocarbon oil and aqueous acid solutions used to treat subterranean rock formations surrounding oil and gas wells. In this case, the amine surfactants were all utilized in the microemulsions as cationic quaternary ammonium salts.
U.S. Pat. No. 4,797,202 discloses N-(hydrocarbyl)-xcex1,xcfx89-alkanediamines as collectors for the recovery of minerals from mineral ores by froth flotation. In particular, the 1:1 adduct of diethylenetriamine and 2-ethylhexyl glycidyl ether was shown to be effective for copper recovery in the froth flotation of copper sulfide.
CH 313 159 discloses a process for the preparation of stable dye and stripper baths containing positively charged amine additives. The baths contain 1:1 adducts of diamines and polyamines and C8 and greater alkylglycidyl ethers and the corresponding alkylated amines formed by subsequent reactions with ethylene oxide, dimethyl sulfate, chloroacetic acid and other reagents.
U.S. Pat. No. 4,311,618 discloses the use of a water soluble cleanser concentrate comprising an ionic surfactant, a non-ionic surfactant, an amphoteric dissociating agent and an organic aprotic solvent. The hydrochloride salt of the 1:2 adduct of diethylenetriamine and 2-ethylhexyl glycidyl ether is shown in Example 5.
JP52018047 discloses adducts prepared by the reaction of polyamines and up to 3 C6-C16 alkyl glycidyl ethers have been utilized as bactericides.
JP 450119973 discloses similar compounds which also contain carboxylate groups have been shown to be effective bactericidal surfactants.
U.S. Pat. No. 3,931,430 discloses the use of reaction products of diamines and polyamines and C4-C16 glycidyl esters and ethers as desensitizers for pressure-sensitive recording sheets. These desensitizers must be soluble in an oil vehicle used to make non-aqueous ink for offset printing.
The present invention relates to the use of the reaction products of polyamines and alkyl glycidyl ethers of the formula:

where
n and m are 2 or 3,
x is 1-6, 
Rxe2x80x2 is a C4 to C22 alkyl group,
for controlling, i.e., reducing, preventing or eliminating, foam in waterborne compositions and industrial processes that otherwise manifest foaming. According to this invention, the foam control agent may be prepared from any C4 to C22 alkyl glycidyl ether and polyamine consistent with the above formula. These foam control agents are low color, low odor, 100% active materials.
Not all alkyl glycidyl ether-capped polyamines are capable of reducing or eliminating foam and certain adducts in fact add problematic foam to waterborne systems. Therefore, the correct combination of polyamine and alkyl glycidyl ether group and an optimum degree of adduction is essential for the reduction and/or elimination of foam. Thus, suitable alkyl glycidyl ether-capped polyamines are those that generate an initial foam height at least 30% less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate (DOSS) when added at 0.1 wt % to the aqueous DOSS solution, as measured according to ASTM D 1173-53 at ambient temperature.
By xe2x80x9cwater-basedxe2x80x9d, xe2x80x9cwaterbornexe2x80x9d, xe2x80x9caqueousxe2x80x9d or xe2x80x9caqueous mediumxe2x80x9d, we mean, for purposes of this invention, a solvent or liquid dispersing medium which comprises water, preferably at least 90 wt %, and most preferably at least 95 wt %, water. Obviously, an all water medium is also included.
As another embodiment of the invention, the foam control agents may be utilized as wetting agents.
There are significant advantages associated with the use of these alkyl glycidyl ether-capped polyamines as foam control agents in water-based compositions and processes and these advantages include one or more of the following:
foam control agents which have low odor and color;
foam control agents which comprise 100% active ingredient and thus do not require carrier fluids, solvents or other additives and exhibit improved shelf stability;
waterborne coatings and inks which have low volatile organic content, thus making these formulations environmentally favorable;
foam control agents capable of reducing the dynamic surface tension of waterborne compositions;
waterborne coatings, inks, adhesives and agricultural formulations which may be applied to a variety of substrates with excellent wetting of substrate surfaces including contaminated and low energy surfaces;
a reduction in coating or printing defects such as orange peel and flow/leveling deficiencies in comparison to conventional foam control agents;
waterborne compositions capable of high speed application and processing; and
industrial processes which have no foam or greatly reduced amounts of problematic foam with a reduction in negative down-stream effects.
This invention relates to the use of the reaction products of certain polyamines and alkyl glycidyl ethers. Although it is widely recognized that such reaction products are mixtures, a major constituent of this mixture may be represented by the formula:

where
n and m are 2 or 3,
x is 1-6, 
Rxe2x80x2 is a C4 to C22 alkyl group,
for the prevention or elimination of foam in waterborne formulations and industrial processes. Preferably and independently or jointly, Rxe2x80x2 is C4-C14 alkyl, x is 1 or 2, and n and m are 2. According to this invention, the foam control agent may be prepared from any C4 to C22 alkyl glycidyl ether and polyamine consistent with the above formula. It is readily apparent according to the formula that the compound may be adducted with from 1 to 5 alkyl glycidyl groups when x is 1 (degree of adduction=1 to 5) and with from 1 to 6 glycidyl groups when x is 2 (degree of adduction=1 to 6).
Suitable alkyl glycidyl ether-capped polyamines are those that generate an initial foam height at least 30% less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate (DOSS) when added at 0.1 wt % to the aqueous DOSS solution, as determined according to ASTM D 1173-53 at ambient temperature, preferably an initial foam height at least 50% less.
It is also desirable that an aqueous solution of the foam control agent exhibits ancillary wetting properties, as demonstrated by a dynamic surface tension of less than or equal to xe2x89xa645 dynes/cm at a concentration of  less than 1 wt % in water at 25xc2x0 C. and 0.1 bubble/second according to the maximum-bubble pressure method. The maximum-bubble-pressure method of measuring surface tension is described in Langmuir 1986, 2, 428-432, which is incorporated by reference.
The excellent defoaming and antifoaming properties of these foam control agents suggest that these materials are likely to find applicability in applications and processes in which the reduction, prevention or knock-down of foam are important. Such applications include protective and decorative coatings, inks, adhesives, agricultural formulations, oil well pumping, petroleum gas scrubbing, cleansing and disinfecting, food processing, pulp and paper processing, fermentation, metal treatment, polymer and chemical synthesis, waste-water treatment and textile dyeing and finishing. In addition, these materials have the ability to also reduce dynamic surface tension of waterborne compositions. Such a combination of performance attributes allow these materials to be used to control and eliminate foam with significantly less deleterious effects in application, making them extremely useful in coatings, inks and adhesives. Moreover, the wetting ability of these foam control agents will allow these materials to be utilized in polymer production and processing without the appearance of negative defects in downstream applications.
These materials may be prepared by the reaction of a polyamine with one or more alkyl glycidyl ethers. The epoxide ring opening reaction may be performed using the amine either neat or in a solvent such as tetrahydrofuran. It is preferred that the alkyl glycidyl ether be added to the amine reagent and that the reaction temperature be maintained between 60 to 120xc2x0 C. The product may be used as made or in a purified form. The reaction products obtained from polyamines and alkyl glycidyl ethers are mixtures, as the hydroxy group generated via the epoxide ring opening reaction may also react with an alkyl glycidyl ether. The reaction illustrated below in which 1 to 10 equivalents alkyl glycidyl ether are reacted with the polyamine shows one of the more common adducts contained in the product mixture:

where R, Rxe2x80x2, m, n and x are as defined above.
All alkyl glycidyl ethers or mixtures of alkyl glycidyl ethers containing the requisite C4 to C22 alkyl substituents may be utilized for the preparation of the capped-polyamine foam control agents of this invention. Alkyl groups which are suitable should have sufficient carbon to confer surface activity, i.e., an ability to act as a foam control agent and reduce the surface tension of water.
The alkyl groups in the alkyl glycidyl ether-capped polyamines of this invention may be the same or different. Alkyl groups may be linear or branched. Examples of suitable alkyl glycidyl ethers include butyl glycidyl ether, iso-butyl glycidyl ether, pentyl glycidyl ether, iso-amyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, octyl glycidyl ether, decyl glycidyl ether, lauryl glycidyl ether, myristyl glycidyl ether, cetyl glycidyl ether and so on.
Examples of polyamines include diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA) and di(aminopropyl)amine (DAPA). Optimal performance for a specific application can be achieved by appropriate manipulation of the starting amine and alkyl glycidyl ether and the degree of adduction.
An amount of alkyl glycidyl ether-capped polyamine that is effective to reduce or eliminate the foam of a water-based, organic compound-containing composition may range from 0.001 to 20 g/100 mL, preferably 0.01 to 10 g/100 mL, of the aqueous composition. Naturally, the most effective amount will depend on the application and the efficiency of the particular foam control agent.
The alkyl glycidyl ether-capped polyamines are suitable for use in an aqueous composition comprising in water an inorganic compound which is a mineral ore or a pigment or an organic compound which is a pigment, a polymerizable monomer, such as addition, condensation and vinyl monomers, an oligomeric resin, a polymeric resin, a detergent, a caustic cleaning agent, a herbicide, a fungicide, an insecticide, or a plant growth modifying agent.
In the following water-based protective or decorative organic coating, ink, adhesive, fountain solution, agricultural and varnish compositions containing an alkyl glycidyl ether-capped polyamine according to the invention, the other listed components of such compositions are those materials well known to the workers in the relevant art.
A typical water-based coating formulation to which the foam control agents of the invention may be added would comprise the following components in an aqueous medium at 30 to 80% xe2x80x9csolidsxe2x80x9d, i.e., listed ingredients:
A typical water-based ink composition to which the foam control agent of the invention may be added would comprise the following components in an aqueous medium at 20 to 60% xe2x80x9csolidsxe2x80x9d, i.e., listed ingredients:
A typical water-based agricultural composition to which the foam control agent of the invention may be added would comprise the following components in an aqueous medium at 0.1 to 80% ingredients:
A typical fountain solution composition for planographic printing to which the foam control agent of the invention may be added would comprise the following components:
A typical pressure sensitive adhesive to which the foam control agent of the invention may be added would comprise the following components:
A typical overprint varnish to which the foam control agent of the invention may be added would comprise the following components:
Examples 1-26 illustrate the synthesis of various foam control agents. All materials were synthesized and characterized via either GC, MALDI or Nuclear Magnetic Resonance (NMR) spectroscopy. Diethylenetriamine (DETA) and di(aminopropyl)amine (DAPA) were purchased as 99% pure from Aldrich Chemical Co. and used as received. The tetraethylenetriamine (TETA) used is sold by Air Products and Chemicals, Inc. as Ancamine(copyright) TETA curing agent which comprises about 67% TETA and also contains tris(2-aminoethyl)amine and piperazine derivatives. The alkylglycidyl ether reagents used are sold by Air Products and Chemicals, Inc. under the trademarks Epodil(copyright) 741 HP, Epodil(copyright) 746 and Epodil(copyright) 748 and contain 98+% n-butyl glycidyl ether, 70-73% 2-ethylhexylglycidyl ether and 75-81% of a C12-C16 mixed-stream glycidyl ether, respectively. The Epodil(copyright) 748 material is predominately lauryl glycidyl ether. For the purposes of this invention these reagents will be referred to as n-butyl glycidyl ether (BGE), 2-ethylhexylglycidylether (EHGE) and C12-C16 alkyl glycidyl ether (CGE).